diffusers/scripts/convert_svd_to_diffusers.py

from diffusers.utils import is_accelerate_available, logging


if is_accelerate_available():
    pass

logger = logging.get_logger(__name__)  # pylint: disable=invalid-name


def create_unet_diffusers_config(original_config, image_size: int, controlnet=False):
    """
    Creates a config for the diffusers based on the config of the LDM model.
    """
    if controlnet:
        unet_params = original_config.model.params.control_stage_config.params
    else:
        if "unet_config" in original_config.model.params and original_config.model.params.unet_config is not None:
            unet_params = original_config.model.params.unet_config.params
        else:
            unet_params = original_config.model.params.network_config.params

    vae_params = original_config.model.params.first_stage_config.params.encoder_config.params

    block_out_channels = [unet_params.model_channels * mult for mult in unet_params.channel_mult]

    down_block_types = []
    resolution = 1
    for i in range(len(block_out_channels)):
        block_type = (
            "CrossAttnDownBlockSpatioTemporal"
            if resolution in unet_params.attention_resolutions
            else "DownBlockSpatioTemporal"
        )
        down_block_types.append(block_type)
        if i != len(block_out_channels) - 1:
            resolution *= 2

    up_block_types = []
    for i in range(len(block_out_channels)):
        block_type = (
            "CrossAttnUpBlockSpatioTemporal"
            if resolution in unet_params.attention_resolutions
            else "UpBlockSpatioTemporal"
        )
        up_block_types.append(block_type)
        resolution //= 2

    if unet_params.transformer_depth is not None:
        transformer_layers_per_block = (
            unet_params.transformer_depth
            if isinstance(unet_params.transformer_depth, int)
            else list(unet_params.transformer_depth)
        )
    else:
        transformer_layers_per_block = 1

    vae_scale_factor = 2 ** (len(vae_params.ch_mult) - 1)

    head_dim = unet_params.num_heads if "num_heads" in unet_params else None
    use_linear_projection = (
        unet_params.use_linear_in_transformer if "use_linear_in_transformer" in unet_params else False
    )
    if use_linear_projection:
        # stable diffusion 2-base-512 and 2-768
        if head_dim is None:
            head_dim_mult = unet_params.model_channels // unet_params.num_head_channels
            head_dim = [head_dim_mult * c for c in list(unet_params.channel_mult)]

    class_embed_type = None
    addition_embed_type = None
    addition_time_embed_dim = None
    projection_class_embeddings_input_dim = None
    context_dim = None

    if unet_params.context_dim is not None:
        context_dim = (
            unet_params.context_dim if isinstance(unet_params.context_dim, int) else unet_params.context_dim[0]
        )

    if "num_classes" in unet_params:
        if unet_params.num_classes == "sequential":
            addition_time_embed_dim = 256
            assert "adm_in_channels" in unet_params
            projection_class_embeddings_input_dim = unet_params.adm_in_channels

    config = {
        "sample_size": image_size // vae_scale_factor,
        "in_channels": unet_params.in_channels,
        "down_block_types": tuple(down_block_types),
        "block_out_channels": tuple(block_out_channels),
        "layers_per_block": unet_params.num_res_blocks,
        "cross_attention_dim": context_dim,
        "attention_head_dim": head_dim,
        "use_linear_projection": use_linear_projection,
        "class_embed_type": class_embed_type,
        "addition_embed_type": addition_embed_type,
        "addition_time_embed_dim": addition_time_embed_dim,
        "projection_class_embeddings_input_dim": projection_class_embeddings_input_dim,
        "transformer_layers_per_block": transformer_layers_per_block,
    }

    if "disable_self_attentions" in unet_params:
        config["only_cross_attention"] = unet_params.disable_self_attentions

    if "num_classes" in unet_params and isinstance(unet_params.num_classes, int):
        config["num_class_embeds"] = unet_params.num_classes

    if controlnet:
        config["conditioning_channels"] = unet_params.hint_channels
    else:
        config["out_channels"] = unet_params.out_channels
        config["up_block_types"] = tuple(up_block_types)

    return config


def assign_to_checkpoint(
    paths,
    checkpoint,
    old_checkpoint,
    attention_paths_to_split=None,
    additional_replacements=None,
    config=None,
    mid_block_suffix="",
):
    """
    This does the final conversion step: take locally converted weights and apply a global renaming to them. It splits
    attention layers, and takes into account additional replacements that may arise.

    Assigns the weights to the new checkpoint.
    """
    assert isinstance(paths, list), "Paths should be a list of dicts containing 'old' and 'new' keys."

    # Splits the attention layers into three variables.
    if attention_paths_to_split is not None:
        for path, path_map in attention_paths_to_split.items():
            old_tensor = old_checkpoint[path]
            channels = old_tensor.shape[0] // 3

            target_shape = (-1, channels) if len(old_tensor.shape) == 3 else (-1)

            num_heads = old_tensor.shape[0] // config["num_head_channels"] // 3

            old_tensor = old_tensor.reshape((num_heads, 3 * channels // num_heads) + old_tensor.shape[1:])
            query, key, value = old_tensor.split(channels // num_heads, dim=1)

            checkpoint[path_map["query"]] = query.reshape(target_shape)
            checkpoint[path_map["key"]] = key.reshape(target_shape)
            checkpoint[path_map["value"]] = value.reshape(target_shape)

    if mid_block_suffix is not None:
        mid_block_suffix = f".{mid_block_suffix}"
    else:
        mid_block_suffix = ""

    for path in paths:
        new_path = path["new"]

        # These have already been assigned
        if attention_paths_to_split is not None and new_path in attention_paths_to_split:
            continue

        # Global renaming happens here
        new_path = new_path.replace("middle_block.0", f"mid_block.resnets.0{mid_block_suffix}")
        new_path = new_path.replace("middle_block.1", "mid_block.attentions.0")
        new_path = new_path.replace("middle_block.2", f"mid_block.resnets.1{mid_block_suffix}")

        if additional_replacements is not None:
            for replacement in additional_replacements:
                new_path = new_path.replace(replacement["old"], replacement["new"])

        if new_path == "mid_block.resnets.0.spatial_res_block.norm1.weight":
            print("yeyy")

        # proj_attn.weight has to be converted from conv 1D to linear
        is_attn_weight = "proj_attn.weight" in new_path or ("attentions" in new_path and "to_" in new_path)
        shape = old_checkpoint[path["old"]].shape
        if is_attn_weight and len(shape) == 3:
            checkpoint[new_path] = old_checkpoint[path["old"]][:, :, 0]
        elif is_attn_weight and len(shape) == 4:
            checkpoint[new_path] = old_checkpoint[path["old"]][:, :, 0, 0]
        else:
            checkpoint[new_path] = old_checkpoint[path["old"]]


def renew_attention_paths(old_list, n_shave_prefix_segments=0):
    """
    Updates paths inside attentions to the new naming scheme (local renaming)
    """
    mapping = []
    for old_item in old_list:
        new_item = old_item

        #         new_item = new_item.replace('norm.weight', 'group_norm.weight')
        #         new_item = new_item.replace('norm.bias', 'group_norm.bias')

        #         new_item = new_item.replace('proj_out.weight', 'proj_attn.weight')
        #         new_item = new_item.replace('proj_out.bias', 'proj_attn.bias')

        #         new_item = shave_segments(new_item, n_shave_prefix_segments=n_shave_prefix_segments)
        new_item = new_item.replace("time_stack", "temporal_transformer_blocks")

        new_item = new_item.replace("time_pos_embed.0.bias", "time_pos_embed.linear_1.bias")
        new_item = new_item.replace("time_pos_embed.0.weight", "time_pos_embed.linear_1.weight")
        new_item = new_item.replace("time_pos_embed.2.bias", "time_pos_embed.linear_2.bias")
        new_item = new_item.replace("time_pos_embed.2.weight", "time_pos_embed.linear_2.weight")

        mapping.append({"old": old_item, "new": new_item})

    return mapping


def shave_segments(path, n_shave_prefix_segments=1):
    """
    Removes segments. Positive values shave the first segments, negative shave the last segments.
    """
    if n_shave_prefix_segments >= 0:
        return ".".join(path.split(".")[n_shave_prefix_segments:])
    else:
        return ".".join(path.split(".")[:n_shave_prefix_segments])


def renew_resnet_paths(old_list, n_shave_prefix_segments=0):
    """
    Updates paths inside resnets to the new naming scheme (local renaming)
    """
    mapping = []
    for old_item in old_list:
        new_item = old_item.replace("in_layers.0", "norm1")
        new_item = new_item.replace("in_layers.2", "conv1")

        new_item = new_item.replace("out_layers.0", "norm2")
        new_item = new_item.replace("out_layers.3", "conv2")

        new_item = new_item.replace("emb_layers.1", "time_emb_proj")
        new_item = new_item.replace("skip_connection", "conv_shortcut")

        new_item = new_item.replace("time_stack.", "")

        new_item = shave_segments(new_item, n_shave_prefix_segments=n_shave_prefix_segments)

        mapping.append({"old": old_item, "new": new_item})

    return mapping


def convert_ldm_unet_checkpoint(
    checkpoint, config, path=None, extract_ema=False, controlnet=False, skip_extract_state_dict=False
):
    """
    Takes a state dict and a config, and returns a converted checkpoint.
    """

    if skip_extract_state_dict:
        unet_state_dict = checkpoint
    else:
        # extract state_dict for UNet
        unet_state_dict = {}
        keys = list(checkpoint.keys())

        unet_key = "model.diffusion_model."

        # at least a 100 parameters have to start with `model_ema` in order for the checkpoint to be EMA
        if sum(k.startswith("model_ema") for k in keys) > 100 and extract_ema:
            logger.warning(f"Checkpoint {path} has both EMA and non-EMA weights.")
            logger.warning(
                "In this conversion only the EMA weights are extracted. If you want to instead extract the non-EMA"
                " weights (useful to continue fine-tuning), please make sure to remove the `--extract_ema` flag."
            )
            for key in keys:
                if key.startswith("model.diffusion_model"):
                    flat_ema_key = "model_ema." + "".join(key.split(".")[1:])
                    unet_state_dict[key.replace(unet_key, "")] = checkpoint.pop(flat_ema_key)
        else:
            if sum(k.startswith("model_ema") for k in keys) > 100:
                logger.warning(
                    "In this conversion only the non-EMA weights are extracted. If you want to instead extract the EMA"
                    " weights (usually better for inference), please make sure to add the `--extract_ema` flag."
                )

            for key in keys:
                if key.startswith(unet_key):
                    unet_state_dict[key.replace(unet_key, "")] = checkpoint.pop(key)

    new_checkpoint = {}

    new_checkpoint["time_embedding.linear_1.weight"] = unet_state_dict["time_embed.0.weight"]
    new_checkpoint["time_embedding.linear_1.bias"] = unet_state_dict["time_embed.0.bias"]
    new_checkpoint["time_embedding.linear_2.weight"] = unet_state_dict["time_embed.2.weight"]
    new_checkpoint["time_embedding.linear_2.bias"] = unet_state_dict["time_embed.2.bias"]

    if config["class_embed_type"] is None:
        # No parameters to port
        ...
    elif config["class_embed_type"] == "timestep" or config["class_embed_type"] == "projection":
        new_checkpoint["class_embedding.linear_1.weight"] = unet_state_dict["label_emb.0.0.weight"]
        new_checkpoint["class_embedding.linear_1.bias"] = unet_state_dict["label_emb.0.0.bias"]
        new_checkpoint["class_embedding.linear_2.weight"] = unet_state_dict["label_emb.0.2.weight"]
        new_checkpoint["class_embedding.linear_2.bias"] = unet_state_dict["label_emb.0.2.bias"]
    else:
        raise NotImplementedError(f"Not implemented `class_embed_type`: {config['class_embed_type']}")

    # if config["addition_embed_type"] == "text_time":
    new_checkpoint["add_embedding.linear_1.weight"] = unet_state_dict["label_emb.0.0.weight"]
    new_checkpoint["add_embedding.linear_1.bias"] = unet_state_dict["label_emb.0.0.bias"]
    new_checkpoint["add_embedding.linear_2.weight"] = unet_state_dict["label_emb.0.2.weight"]
    new_checkpoint["add_embedding.linear_2.bias"] = unet_state_dict["label_emb.0.2.bias"]

    new_checkpoint["conv_in.weight"] = unet_state_dict["input_blocks.0.0.weight"]
    new_checkpoint["conv_in.bias"] = unet_state_dict["input_blocks.0.0.bias"]

    new_checkpoint["conv_norm_out.weight"] = unet_state_dict["out.0.weight"]
    new_checkpoint["conv_norm_out.bias"] = unet_state_dict["out.0.bias"]
    new_checkpoint["conv_out.weight"] = unet_state_dict["out.2.weight"]
    new_checkpoint["conv_out.bias"] = unet_state_dict["out.2.bias"]

    # Retrieves the keys for the input blocks only
    num_input_blocks = len({".".join(layer.split(".")[:2]) for layer in unet_state_dict if "input_blocks" in layer})
    input_blocks = {
        layer_id: [key for key in unet_state_dict if f"input_blocks.{layer_id}" in key]
        for layer_id in range(num_input_blocks)
    }

    # Retrieves the keys for the middle blocks only
    num_middle_blocks = len({".".join(layer.split(".")[:2]) for layer in unet_state_dict if "middle_block" in layer})
    middle_blocks = {
        layer_id: [key for key in unet_state_dict if f"middle_block.{layer_id}" in key]
        for layer_id in range(num_middle_blocks)
    }

    # Retrieves the keys for the output blocks only
    num_output_blocks = len({".".join(layer.split(".")[:2]) for layer in unet_state_dict if "output_blocks" in layer})
    output_blocks = {
        layer_id: [key for key in unet_state_dict if f"output_blocks.{layer_id}" in key]
        for layer_id in range(num_output_blocks)
    }

    for i in range(1, num_input_blocks):
        block_id = (i - 1) // (config["layers_per_block"] + 1)
        layer_in_block_id = (i - 1) % (config["layers_per_block"] + 1)

        spatial_resnets = [
            key
            for key in input_blocks[i]
            if f"input_blocks.{i}.0" in key
            and (
                f"input_blocks.{i}.0.op" not in key
                and f"input_blocks.{i}.0.time_stack" not in key
                and f"input_blocks.{i}.0.time_mixer" not in key
            )
        ]
        temporal_resnets = [key for key in input_blocks[i] if f"input_blocks.{i}.0.time_stack" in key]
        # import ipdb; ipdb.set_trace()
        attentions = [key for key in input_blocks[i] if f"input_blocks.{i}.1" in key]

        if f"input_blocks.{i}.0.op.weight" in unet_state_dict:
            new_checkpoint[f"down_blocks.{block_id}.downsamplers.0.conv.weight"] = unet_state_dict.pop(
                f"input_blocks.{i}.0.op.weight"
            )
            new_checkpoint[f"down_blocks.{block_id}.downsamplers.0.conv.bias"] = unet_state_dict.pop(
                f"input_blocks.{i}.0.op.bias"
            )

        paths = renew_resnet_paths(spatial_resnets)
        meta_path = {
            "old": f"input_blocks.{i}.0",
            "new": f"down_blocks.{block_id}.resnets.{layer_in_block_id}.spatial_res_block",
        }
        assign_to_checkpoint(
            paths, new_checkpoint, unet_state_dict, additional_replacements=[meta_path], config=config
        )

        paths = renew_resnet_paths(temporal_resnets)
        meta_path = {
            "old": f"input_blocks.{i}.0",
            "new": f"down_blocks.{block_id}.resnets.{layer_in_block_id}.temporal_res_block",
        }
        assign_to_checkpoint(
            paths, new_checkpoint, unet_state_dict, additional_replacements=[meta_path], config=config
        )

        # TODO resnet time_mixer.mix_factor
        if f"input_blocks.{i}.0.time_mixer.mix_factor" in unet_state_dict:
            new_checkpoint[f"down_blocks.{block_id}.resnets.{layer_in_block_id}.time_mixer.mix_factor"] = (
                unet_state_dict[f"input_blocks.{i}.0.time_mixer.mix_factor"]
            )

        if len(attentions):
            paths = renew_attention_paths(attentions)
            meta_path = {"old": f"input_blocks.{i}.1", "new": f"down_blocks.{block_id}.attentions.{layer_in_block_id}"}
            # import ipdb; ipdb.set_trace()
            assign_to_checkpoint(
                paths, new_checkpoint, unet_state_dict, additional_replacements=[meta_path], config=config
            )

    resnet_0 = middle_blocks[0]
    attentions = middle_blocks[1]
    resnet_1 = middle_blocks[2]

    resnet_0_spatial = [key for key in resnet_0 if "time_stack" not in key and "time_mixer" not in key]
    resnet_0_paths = renew_resnet_paths(resnet_0_spatial)
    # import ipdb; ipdb.set_trace()
    assign_to_checkpoint(
        resnet_0_paths, new_checkpoint, unet_state_dict, config=config, mid_block_suffix="spatial_res_block"
    )

    resnet_0_temporal = [key for key in resnet_0 if "time_stack" in key and "time_mixer" not in key]
    resnet_0_paths = renew_resnet_paths(resnet_0_temporal)
    assign_to_checkpoint(
        resnet_0_paths, new_checkpoint, unet_state_dict, config=config, mid_block_suffix="temporal_res_block"
    )

    resnet_1_spatial = [key for key in resnet_1 if "time_stack" not in key and "time_mixer" not in key]
    resnet_1_paths = renew_resnet_paths(resnet_1_spatial)
    assign_to_checkpoint(
        resnet_1_paths, new_checkpoint, unet_state_dict, config=config, mid_block_suffix="spatial_res_block"
    )

    resnet_1_temporal = [key for key in resnet_1 if "time_stack" in key and "time_mixer" not in key]
    resnet_1_paths = renew_resnet_paths(resnet_1_temporal)
    assign_to_checkpoint(
        resnet_1_paths, new_checkpoint, unet_state_dict, config=config, mid_block_suffix="temporal_res_block"
    )

    new_checkpoint["mid_block.resnets.0.time_mixer.mix_factor"] = unet_state_dict[
        "middle_block.0.time_mixer.mix_factor"
    ]
    new_checkpoint["mid_block.resnets.1.time_mixer.mix_factor"] = unet_state_dict[
        "middle_block.2.time_mixer.mix_factor"
    ]

    attentions_paths = renew_attention_paths(attentions)
    meta_path = {"old": "middle_block.1", "new": "mid_block.attentions.0"}
    assign_to_checkpoint(
        attentions_paths, new_checkpoint, unet_state_dict, additional_replacements=[meta_path], config=config
    )

    for i in range(num_output_blocks):
        block_id = i // (config["layers_per_block"] + 1)
        layer_in_block_id = i % (config["layers_per_block"] + 1)
        output_block_layers = [shave_segments(name, 2) for name in output_blocks[i]]
        output_block_list = {}

        for layer in output_block_layers:
            layer_id, layer_name = layer.split(".")[0], shave_segments(layer, 1)
            if layer_id in output_block_list:
                output_block_list[layer_id].append(layer_name)
            else:
                output_block_list[layer_id] = [layer_name]

        if len(output_block_list) > 1:
            spatial_resnets = [
                key
                for key in output_blocks[i]
                if f"output_blocks.{i}.0" in key
                and (f"output_blocks.{i}.0.time_stack" not in key and "time_mixer" not in key)
            ]
            # import ipdb; ipdb.set_trace()

            temporal_resnets = [key for key in output_blocks[i] if f"output_blocks.{i}.0.time_stack" in key]

            paths = renew_resnet_paths(spatial_resnets)
            meta_path = {
                "old": f"output_blocks.{i}.0",
                "new": f"up_blocks.{block_id}.resnets.{layer_in_block_id}.spatial_res_block",
            }
            assign_to_checkpoint(
                paths, new_checkpoint, unet_state_dict, additional_replacements=[meta_path], config=config
            )

            paths = renew_resnet_paths(temporal_resnets)
            meta_path = {
                "old": f"output_blocks.{i}.0",
                "new": f"up_blocks.{block_id}.resnets.{layer_in_block_id}.temporal_res_block",
            }
            assign_to_checkpoint(
                paths, new_checkpoint, unet_state_dict, additional_replacements=[meta_path], config=config
            )

            if f"output_blocks.{i}.0.time_mixer.mix_factor" in unet_state_dict:
                new_checkpoint[f"up_blocks.{block_id}.resnets.{layer_in_block_id}.time_mixer.mix_factor"] = (
                    unet_state_dict[f"output_blocks.{i}.0.time_mixer.mix_factor"]
                )

            output_block_list = {k: sorted(v) for k, v in output_block_list.items()}
            if ["conv.bias", "conv.weight"] in output_block_list.values():
                index = list(output_block_list.values()).index(["conv.bias", "conv.weight"])
                new_checkpoint[f"up_blocks.{block_id}.upsamplers.0.conv.weight"] = unet_state_dict[
                    f"output_blocks.{i}.{index}.conv.weight"
                ]
                new_checkpoint[f"up_blocks.{block_id}.upsamplers.0.conv.bias"] = unet_state_dict[
                    f"output_blocks.{i}.{index}.conv.bias"
                ]

                # Clear attentions as they have been attributed above.
                if len(attentions) == 2:
                    attentions = []

            attentions = [key for key in output_blocks[i] if f"output_blocks.{i}.1" in key and "conv" not in key]
            if len(attentions):
                paths = renew_attention_paths(attentions)
                # import ipdb; ipdb.set_trace()
                meta_path = {
                    "old": f"output_blocks.{i}.1",
                    "new": f"up_blocks.{block_id}.attentions.{layer_in_block_id}",
                }
                assign_to_checkpoint(
                    paths, new_checkpoint, unet_state_dict, additional_replacements=[meta_path], config=config
                )
        else:
            spatial_layers = [
                layer for layer in output_block_layers if "time_stack" not in layer and "time_mixer" not in layer
            ]
            resnet_0_paths = renew_resnet_paths(spatial_layers, n_shave_prefix_segments=1)
            # import ipdb; ipdb.set_trace()
            for path in resnet_0_paths:
                old_path = ".".join(["output_blocks", str(i), path["old"]])
                new_path = ".".join(
                    ["up_blocks", str(block_id), "resnets", str(layer_in_block_id), "spatial_res_block", path["new"]]
                )

                new_checkpoint[new_path] = unet_state_dict[old_path]

            temporal_layers = [
                layer for layer in output_block_layers if "time_stack" in layer and "time_mixer" not in key
            ]
            resnet_0_paths = renew_resnet_paths(temporal_layers, n_shave_prefix_segments=1)
            # import ipdb; ipdb.set_trace()
            for path in resnet_0_paths:
                old_path = ".".join(["output_blocks", str(i), path["old"]])
                new_path = ".".join(
                    ["up_blocks", str(block_id), "resnets", str(layer_in_block_id), "temporal_res_block", path["new"]]
                )

                new_checkpoint[new_path] = unet_state_dict[old_path]

            new_checkpoint["up_blocks.0.resnets.0.time_mixer.mix_factor"] = unet_state_dict[
                f"output_blocks.{str(i)}.0.time_mixer.mix_factor"
            ]

    return new_checkpoint


def conv_attn_to_linear(checkpoint):
    keys = list(checkpoint.keys())
    attn_keys = ["to_q.weight", "to_k.weight", "to_v.weight"]
    for key in keys:
        if ".".join(key.split(".")[-2:]) in attn_keys:
            if checkpoint[key].ndim > 2:
                checkpoint[key] = checkpoint[key][:, :, 0, 0]
        elif "proj_attn.weight" in key:
            if checkpoint[key].ndim > 2:
                checkpoint[key] = checkpoint[key][:, :, 0]


def renew_vae_resnet_paths(old_list, n_shave_prefix_segments=0, is_temporal=False):
    """
    Updates paths inside resnets to the new naming scheme (local renaming)
    """
    mapping = []
    for old_item in old_list:
        new_item = old_item

        # Temporal resnet
        new_item = old_item.replace("in_layers.0", "norm1")
        new_item = new_item.replace("in_layers.2", "conv1")

        new_item = new_item.replace("out_layers.0", "norm2")
        new_item = new_item.replace("out_layers.3", "conv2")

        new_item = new_item.replace("skip_connection", "conv_shortcut")

        new_item = new_item.replace("time_stack.", "temporal_res_block.")

        # Spatial resnet
        new_item = new_item.replace("conv1", "spatial_res_block.conv1")
        new_item = new_item.replace("norm1", "spatial_res_block.norm1")

        new_item = new_item.replace("conv2", "spatial_res_block.conv2")
        new_item = new_item.replace("norm2", "spatial_res_block.norm2")

        new_item = new_item.replace("nin_shortcut", "spatial_res_block.conv_shortcut")

        new_item = new_item.replace("mix_factor", "spatial_res_block.time_mixer.mix_factor")

        new_item = shave_segments(new_item, n_shave_prefix_segments=n_shave_prefix_segments)

        mapping.append({"old": old_item, "new": new_item})

    return mapping


def renew_vae_attention_paths(old_list, n_shave_prefix_segments=0):
    """
    Updates paths inside attentions to the new naming scheme (local renaming)
    """
    mapping = []
    for old_item in old_list:
        new_item = old_item

        new_item = new_item.replace("norm.weight", "group_norm.weight")
        new_item = new_item.replace("norm.bias", "group_norm.bias")

        new_item = new_item.replace("q.weight", "to_q.weight")
        new_item = new_item.replace("q.bias", "to_q.bias")

        new_item = new_item.replace("k.weight", "to_k.weight")
        new_item = new_item.replace("k.bias", "to_k.bias")

        new_item = new_item.replace("v.weight", "to_v.weight")
        new_item = new_item.replace("v.bias", "to_v.bias")

        new_item = new_item.replace("proj_out.weight", "to_out.0.weight")
        new_item = new_item.replace("proj_out.bias", "to_out.0.bias")

        new_item = shave_segments(new_item, n_shave_prefix_segments=n_shave_prefix_segments)

        mapping.append({"old": old_item, "new": new_item})

    return mapping


def convert_ldm_vae_checkpoint(checkpoint, config):
    # extract state dict for VAE
    vae_state_dict = {}
    keys = list(checkpoint.keys())
    vae_key = "first_stage_model." if any(k.startswith("first_stage_model.") for k in keys) else ""
    for key in keys:
        if key.startswith(vae_key):
            vae_state_dict[key.replace(vae_key, "")] = checkpoint.get(key)

    new_checkpoint = {}

    new_checkpoint["encoder.conv_in.weight"] = vae_state_dict["encoder.conv_in.weight"]
    new_checkpoint["encoder.conv_in.bias"] = vae_state_dict["encoder.conv_in.bias"]
    new_checkpoint["encoder.conv_out.weight"] = vae_state_dict["encoder.conv_out.weight"]
    new_checkpoint["encoder.conv_out.bias"] = vae_state_dict["encoder.conv_out.bias"]
    new_checkpoint["encoder.conv_norm_out.weight"] = vae_state_dict["encoder.norm_out.weight"]
    new_checkpoint["encoder.conv_norm_out.bias"] = vae_state_dict["encoder.norm_out.bias"]

    new_checkpoint["decoder.conv_in.weight"] = vae_state_dict["decoder.conv_in.weight"]
    new_checkpoint["decoder.conv_in.bias"] = vae_state_dict["decoder.conv_in.bias"]
    new_checkpoint["decoder.conv_out.weight"] = vae_state_dict["decoder.conv_out.weight"]
    new_checkpoint["decoder.conv_out.bias"] = vae_state_dict["decoder.conv_out.bias"]
    new_checkpoint["decoder.conv_norm_out.weight"] = vae_state_dict["decoder.norm_out.weight"]
    new_checkpoint["decoder.conv_norm_out.bias"] = vae_state_dict["decoder.norm_out.bias"]
    new_checkpoint["decoder.time_conv_out.weight"] = vae_state_dict["decoder.time_mix_conv.weight"]
    new_checkpoint["decoder.time_conv_out.bias"] = vae_state_dict["decoder.time_mix_conv.bias"]

    # new_checkpoint["quant_conv.weight"] = vae_state_dict["quant_conv.weight"]
    # new_checkpoint["quant_conv.bias"] = vae_state_dict["quant_conv.bias"]
    # new_checkpoint["post_quant_conv.weight"] = vae_state_dict["post_quant_conv.weight"]
    # new_checkpoint["post_quant_conv.bias"] = vae_state_dict["post_quant_conv.bias"]

    # Retrieves the keys for the encoder down blocks only
    num_down_blocks = len({".".join(layer.split(".")[:3]) for layer in vae_state_dict if "encoder.down" in layer})
    down_blocks = {
        layer_id: [key for key in vae_state_dict if f"down.{layer_id}" in key] for layer_id in range(num_down_blocks)
    }

    # Retrieves the keys for the decoder up blocks only
    num_up_blocks = len({".".join(layer.split(".")[:3]) for layer in vae_state_dict if "decoder.up" in layer})
    up_blocks = {
        layer_id: [key for key in vae_state_dict if f"up.{layer_id}" in key] for layer_id in range(num_up_blocks)
    }

    for i in range(num_down_blocks):
        resnets = [key for key in down_blocks[i] if f"down.{i}" in key and f"down.{i}.downsample" not in key]

        if f"encoder.down.{i}.downsample.conv.weight" in vae_state_dict:
            new_checkpoint[f"encoder.down_blocks.{i}.downsamplers.0.conv.weight"] = vae_state_dict.pop(
                f"encoder.down.{i}.downsample.conv.weight"
            )
            new_checkpoint[f"encoder.down_blocks.{i}.downsamplers.0.conv.bias"] = vae_state_dict.pop(
                f"encoder.down.{i}.downsample.conv.bias"
            )

        paths = renew_vae_resnet_paths(resnets)
        meta_path = {"old": f"down.{i}.block", "new": f"down_blocks.{i}.resnets"}
        assign_to_checkpoint(paths, new_checkpoint, vae_state_dict, additional_replacements=[meta_path], config=config)

    mid_resnets = [key for key in vae_state_dict if "encoder.mid.block" in key]
    num_mid_res_blocks = 2
    for i in range(1, num_mid_res_blocks + 1):
        resnets = [key for key in mid_resnets if f"encoder.mid.block_{i}" in key]

        paths = renew_vae_resnet_paths(resnets)
        meta_path = {"old": f"mid.block_{i}", "new": f"mid_block.resnets.{i - 1}"}
        assign_to_checkpoint(paths, new_checkpoint, vae_state_dict, additional_replacements=[meta_path], config=config)

    mid_attentions = [key for key in vae_state_dict if "encoder.mid.attn" in key]
    paths = renew_vae_attention_paths(mid_attentions)
    meta_path = {"old": "mid.attn_1", "new": "mid_block.attentions.0"}
    assign_to_checkpoint(paths, new_checkpoint, vae_state_dict, additional_replacements=[meta_path], config=config)
    conv_attn_to_linear(new_checkpoint)

    for i in range(num_up_blocks):
        block_id = num_up_blocks - 1 - i

        resnets = [
            key for key in up_blocks[block_id] if f"up.{block_id}" in key and f"up.{block_id}.upsample" not in key
        ]

        if f"decoder.up.{block_id}.upsample.conv.weight" in vae_state_dict:
            new_checkpoint[f"decoder.up_blocks.{i}.upsamplers.0.conv.weight"] = vae_state_dict[
                f"decoder.up.{block_id}.upsample.conv.weight"
            ]
            new_checkpoint[f"decoder.up_blocks.{i}.upsamplers.0.conv.bias"] = vae_state_dict[
                f"decoder.up.{block_id}.upsample.conv.bias"
            ]

        paths = renew_vae_resnet_paths(resnets)
        meta_path = {"old": f"up.{block_id}.block", "new": f"up_blocks.{i}.resnets"}
        assign_to_checkpoint(paths, new_checkpoint, vae_state_dict, additional_replacements=[meta_path], config=config)

    mid_resnets = [key for key in vae_state_dict if "decoder.mid.block" in key]
    num_mid_res_blocks = 2
    for i in range(1, num_mid_res_blocks + 1):
        resnets = [key for key in mid_resnets if f"decoder.mid.block_{i}" in key]

        paths = renew_vae_resnet_paths(resnets)
        meta_path = {"old": f"mid.block_{i}", "new": f"mid_block.resnets.{i - 1}"}
        assign_to_checkpoint(paths, new_checkpoint, vae_state_dict, additional_replacements=[meta_path], config=config)

    mid_attentions = [key for key in vae_state_dict if "decoder.mid.attn" in key]
    paths = renew_vae_attention_paths(mid_attentions)
    meta_path = {"old": "mid.attn_1", "new": "mid_block.attentions.0"}
    assign_to_checkpoint(paths, new_checkpoint, vae_state_dict, additional_replacements=[meta_path], config=config)
    conv_attn_to_linear(new_checkpoint)
    return new_checkpoint